Thermostatic switch



Sept; 12, 1950 J. T. CARLSON muosmnc swn'cn Filed April 17, 1947 Inventor John T. Carlson Patented Sept. 12, 1950 'rnaamos'ra'rro swrrcn John T. Carlson, Grand Rapids, Mlola, assignor,

direct and mesne assignments, to Donald L.

Chafi'ee, Grand Rapids, Mich.

Application April 17, 1947, Serial No. 741,981

4 Claims.

installed is endangered by abnormal temperatures, either hot or cold, as the case may be.

The objects and purposes of this invention as a "fire guard are as follows:

1. To provide a snap or kiss action switch adapted to provide a sensitive instrument to readily detect abnormal temperatures in a home or any building or any type of heat generating equipment, and to cause the automatic sounding of an audible alarm or other equivalent warning device such as a bell or any other device. It is designed to function unfailingly when surrounding temperature above the predetermined setting is reached.

2. To provide a low cost unit which may be installed in homes and readily connected directly to the doorbell circuit or to a separate bell or other warning device as desired, thereby making the entire cost and the installation appreciably economical.

3. To provide an inexpensive automatic warnin device which can be installed very easily and,

simply, and will not require the work of trained experts.

4. To provide a fire guard which will be capable of warning the Occupants of any home or any temperature below the desired setting is reached.

2. To provide a freeze guard" which may be connected directly to the doorbell circuit or to a separate bell or other warning device as desired.

3. To provide a freeze guard which is so simply constructed that it can be manufactured at a low cost and will therefor fall within the reach of any owners of deep freeze systems.

4. To provide a freeze guard which may be installed extremely simply and economically.

Briefly, the invention pertains to a thermostat or a thermostatically operated switch placed on the inside of a refrigeration unit and connected to a bell or any other signalling device located on the outside of the freeze unit or at any other convenient desirable location for the purpose of sounding an alarm if the temperature, for any reason, should rise above a safe temperature for preserving the food stored in the freeze compartment, thus giving warning in ample time to correct the difficulty with the refrigeration machine before spoilage will take place.

Other objects and advantages of the invention will become more readily apparent from the following description and the accompanying illustrative drawings.

In the sheet of drawings, wherein like numerals are employed to designate like parts throughout the same:

Figure 1 is a fragmentary view of a diagrammatic character showing a part of a building building at any time of the day or night of an immediate danger of fire. Such warning will enable the occupants to take care of the danger of fire by removing or controlling the fire hazard; or if that cannot be done with safety, then by affording them an opportunity to escape from the danger zone. This will be of greatest importance during the night when altogether too often fires creep up on the occupants of a home or building without any warning, and frequently without affording the occupants any opportunity to escape with safety.

5. To provide a fire guard which is simply constructed and can be manufactured at such a low cost that it will definitely fall within the reach of everyone desiring such protection.

Other objects and purposes of the invention it and when used as a freeze guard are as follows:

1. To provide a low-cost warning device which may be installed in home deep freeze units or in any commercial deep freeze units to cause the sounding of an alarm or signalling device when which may be said to include a floor and cellar, furnace in the cellar, bell circuit and the improved switch devices included in the bell circuit;

Figure 2 is an elevational view of the switch or circuit make and break device per se;

Figure 3 is an edge or rim elevation of same;

Figure 4 is a view based on Figure 2 with the lid or cover removed to show the thermal means;

Figure 5 is a view similar to Figure 4 but showing a modified construction;

Figure 6 is a fragmentary detail section on the line 66 of Figure 5; v

Figure 7 is a fragmentary elevational view of the hub of the device; and,

Figure 8 an elevational view of the cover.

Referring now to the drawings and to Figures 2, 3, 4 and 8, the casing comprises a circular cuplike shell ill of suitable material but preferably of aluminum including a marginal rim H. The rim is provided at a predetermined point with an aperture having a grommet or suitable collar I! mounted therein to accommodate anchored ends of the current conducting wires it and It. The

wire proper, the part ii. is anchored and groundedontheinterior oftherimasshowninFigure4 as at I! (Fig. 4). The opposite wire end It is laterally bent and attached to the post in the binding post assembly II. The post proper I1 extends into the shell for coaction with a contact element I I on a bi-metallic movable contact device II. This is of the usual laminated or twopart construction and has one end anchored as at II on the rim of the shell. The open side of the shell is closed, in practice, by a suitable closing cap II (see Figure 8) which is snapped into place as shown. A suitable hub 22 is provided and this has reduced ends which flt into openings provided in the shell and cover. The opening in the cover is shown in Figure 8 at 23. The ends, that is the reduced ends of the tubular hub pin are denoted by the numerals 24 and 25 and are flattened and headed to maintain the parts assembled as indicated in Figure 3. That is to say, by thus mashingthe reduced ends of the hub and securing same to the shell and cover, a complete casing is provided .for the mechanism.

At this point I direct attention to the diagrammatic fragmentary view identified as Figure 1. Here the floor of the building is indicated at A, a wall is-denoted at B, a bell, an ordinary doorbell, is denoted at C, the furnace at D and the wiring in the bell hook-up is denoted at E. Here I have shown two of the fire guards, so-called, and denoted by the reference letters S. This view is merely to show that fire guards may be incorporated in an ordinary bell system and may be situated either in the room, in the cellar close to the furnace or' wherever the user finds it most satisfactory to install same.

Reference is had at this time to the modification covered in Figures 5, 6 and '7. Here the cuplike aluminum shell or casing proper is denoted by the numeral 26, includes a rim 2'! having a suitable slot or aperture II to let in the electric conductors 29 and 3'. Also, the central hub 3i has reduced ends 32 and 33 whereby it is secured in place. Thereis a notch in the central portion of the hub as indicated at 34 and this serves to permit the flattened end portion 35 to be suitably hammered and wedged in place for secure anchorage purposes. On the interior of the shell is a block of insulation 16 fastened in place at 360. This block has an eyelet or grommet 31a carrying an outstanding silver contact pin 31 (see Figure 6). In addition, one end portion of said pin car-rim a small clip 38 with a downbent hook 39 which hook serves to accommodate the bare-end 40 of the cable or conductor 29. In this adaptation the bi-metallic heat responsive arm or circuit make and break element ll (see Figure is anchored in place as at 42. The length and curvature and bi-metallic strength of the arm is such that the hooked free end portion 43 sweeps in an arcuate path clear of the contact pin 31. A spring follower finger 44 is fastened at 45 to intermediate portion of the thermal arm. This finger 44 is adapted to sweep in a path to engage the contact pin 31. It follows that when the heat responsive element is acted upon by abnormal heat, it sweeps the finger 44 into contact with the contact pin 31, thus closing the alarm circuit.

It sometimes happens that in a bi-metallic element of the type shown, the potential travel of the arm, in its effort to straighten out, will exert too much pressure on the relatively stationary contact element, for example, the pin 31. Thus by providing a follow through and adaptor finger 44, the latter finger will yield sufllciently to pers 4 mt the bi-metallic member to pass on beyond the contact pin while holding the contact finger in electrical contact with the pin at all times.

The thermal switch shown may be operated from either low voltage or standard house current, but a low voltage thermostat definitely will be advantageous from the standpoint of cost as well as simplifying the installation. It is intended that the thermal element will be set at' a predetermined, permanent setting, completely enclosed and sealed to avoid any possibility of tampering.

In actual practice heat will cause the bi-metal strip to expand and when it has expanded sumciently it will then make contact with the silver contact pin which pin is connected to the second lead wire. This contact will thereby close the circuit and set of! the alarm or signalling device. If connected to a bell, the bell will continue to ring as long as heat permits the contact to be maintained. Such continuous sounding of the alarm will in itself be sufilcient to distinguish it from the ordinary doorbell ring or other signalling device.

A careful consideration of the foregoing description in conjunction with the invention as illustrated in the drawings will enable the reader to obtain a clear understanding and impression of the alleged features of merit and novelty sufficient to clarify the construction of the invention as hereinafter claimed.

Minor changes in shape, size, materials and rearrangement of parts may be resorted to in actual practice so long as no departure" is made from the invention as claimed.

What is claimed as new is:

1. In a circuit make and break device of the class described, a hollow casing including a cuplike shell portion and a cover portion, the shell portion having an apertured rim, a centrally located hub in said casing, wires extending through the aperture in said rim and into the casing, the inner end of one wire being electrically connected with said hub, a block of insulation riveted at one end in said casing, the opposite end of said block having an aperture and a' grommet fitted into said aperture, a contact pin having one end portion fitted frictionally and removabl in said grommet and the other end portion extending laterally beyond an adjacent surface of the block, a clip attached to the intermediate portion of said pin, said clip terminating in a hook overhanging an edge of the block, an adjacent end portion of the remaining wire being connected to said hook, and a bi-metalllc thermostat having one end anchored in said casing and its opposite end portion swingable toward and from said contact pin.

2. The structure specified in claim 1, said thermostat embodying a bi-metallic arm and a free contact finger connected to the swingable end portion of said bi-metallic arm, the tip portion of said finger being movable toward and from said contact pin, said arm having its free end portion restricted to swing in an are cut of the path of said contact pin, said contact finger being resilient and having its tip portion swingable in an arcuate path to come into engagement with said pin, whereby said arm may approach and swing clear 01" and beyond said contact pin while said finger remains in electrical engagement with the contact pin.

3. Circuit make and break means for use in a casing of the class described comprising a. block of insulation material provided at one end with means for mounting same in the casing, said block being provided at its opposite end with a socket, said socket being lined with a bushing, a metallic clip provided at one end with a lateral wire accommodating hook, a metallic contact pin connected with the opposite end 01' said clip and having end portions projecting laterally beyond said clip, one end portion being adapted to be titted irictionall and telescopically into said bushing.

4. A circuit make and break switch of the class shown and described embodying an aluminum cup-like shell portion including an apertured rim and a centrally apertured body portion, 9, hollow rivet havin one end spun and anchored in the aperture in said body portion, wires extending through the aperture in said rim and into said shell, the inner end of one wire being electrically anchored on said hollow rivet, a clip attached to the coacting end of the remaining wire, said clip having a contact pin attached rigidly thereto, a block of insulation anchored at one end to said body portion and located eccentrically with respect to said hollow rivet, the opposite end portion of said block being provided with a socket, one end of said contact pin being removably but frictionally lodged in said socket and the opposite end of the pin projecting at right angles to the body portion and parallel to said rim portion and also parallel to said hollow rivet, and a bi-metallic thermostat having a thermal responsive arm anchored at one end to said rim, the opposite free end being swingable in a path between the rim and hollow rivet free of engagement with said contact pin, and a flexible contact finger secured to the free swingable end portion of said arm and projecting beyond said free end portion and swingable into contact with said contact pin.

JOHN T. CARLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATI'DITS Number Name Date 783,376 Howe Feb. 21, 1905 1,387,050 Haslinger Aug. 9, 1921 2,383,533 Crlse Aug. 28, 1945 

